Information about "Chang 'e I"

Chang 'e-1 was successfully launched in 20071October 24th 18: 05: 04!

18: 07 separation of primary and secondary rockets

The fairing separates the rocket from the atmosphere.

18: 10 rocket two-stage separation

18: 65438+

18: 25 the satellite entered the initial earth orbit.

18: 26 secondary ignition of three-stage rocket

18: 28 Secondary shutdown of three-stage rocket engine

18: 29, the satellite separated from the satellite entered the super-geosynchronous orbit with perigee of 205km and apogee of 50930km and period of16 h.

18: 36 The satellite accusation was transferred to Beijing Aerospace Control Center.

Satellite solar panels open.

2007124 October 19: 00 confirmed the successful launch.

In 20071October 25th 17: 55, the first orbit change was completed! After the command was issued 130 seconds, the perigee altitude of the satellite was raised from about 200 km to about 600 km, and the orbit transfer was a complete success. This orbit change shows that the propulsion system of Chang 'e-1 satellite works normally, and it also lays the foundation for the next three perigee orbit changes. Chang 'e-1 satellite orbited once and a half in an elliptical orbit with a period of about 16 hours, and then changed its orbit at the second apogee.

2007126 October 17: 44, Wangyuan No.3 reported that Chang 'e-1 satellite successfully implemented the second orbit change! This is the first perigee orbit change of the satellite.

Chang 'e-1 satellite will enter a 24-hour periodic orbit after the second orbit change. The apogee height has increased from more than 50,000 kilometers to more than 70,000 kilometers.

On October 29th, 65438/kloc-0, the perigee orbit was changed for the second time, and the apogee height of the satellite was increased from more than 70,000 kilometers to120,000 kilometers, which set a new TT&C record for the farthest space in China. Enter a 48-hour periodic orbit around the earth. At 0 10: 39, 18: 00 Beijing time, it was reported that the satellite was successfully put into orbit for the third time!

10,31,17: 25, the perigee orbit was changed for the third time, and the apogee height of the satellite was increased from12,000 km to 370,000 km, and it entered the 1 14-hour monthly transfer orbit.

165438+ arrived 200 kilometers away from the moon on10.5, and entered the lunar orbit for the first time in recent months/kloc-0.2 hour.

165438+1October 6, the second braking in recent months entered the 3.5-hour track for 3 laps.

165438+1October 7, the third braking entry in recent months 127 minutes, the lunar polar orbit began to work, and 30 songs were sent back to the ground.

Chang 'e-1 is China's first artificial satellite orbiting the moon. Named after China's ancient mythical figure Chang 'e, it was launched in xichang satellite launch center at about 18: 05 (UTC+8: 00) on October 24, 2007, and the whole process of "flying to the moon" took about 8-9 days. It is estimated that the total weight of the satellite is about 2350kg and its service life is more than 1 year. The main detection objectives of the satellite are: to obtain three-dimensional images of the lunar surface; Analyze the content of useful elements on the surface of the moon and the distribution characteristics of material types; Detect the thickness of lunar soil and the space environment from the earth to the moon.

general situation

Chang 'e-1 satellite was developed by China Academy of Space Technology and named after Chang 'e, an ancient mythical figure in China. It is mainly used to obtain three-dimensional images of the lunar surface, analyze the distribution characteristics of related material elements on the lunar surface, detect the thickness of lunar soil, and detect the space environment of the earth and the moon. In the initial sample development stage, two initial sample satellites, namely the electric satellite and the structural satellite, undertake satellite testing. Chang 'e-1 platform is developed on the basis of China's mature Dongfanghong-3 satellite platform, with a star diameter of 2,000 mm×1720 mm× 2,200 mm, fully inheriting the existing mature technologies and products of China Resources-2 satellite and China-Pakistan Earth Resources Satellite, and making adaptive transformation. The so-called adaptive transformation is an innovation in inheritance and a breakthrough in a number of key technologies.

Chang 'e-1 is a cube with two solar panels on each side, with a maximum span of 18.438+0m, a weight of 2350kg and a working life of one year. It will run in a circular polar orbit 200 kilometers from the surface of the moon.

The satellite platform consists of nine subsystems: structural subsystem, thermal control subsystem, guidance, navigation and control subsystem, propulsion subsystem, data management subsystem, measurement and control data transmission subsystem, directional antenna subsystem and payload. These subsystems perform their respective duties and work together to ensure the smooth completion of the lunar exploration mission. The payload on the satellite is used to complete the scientific exploration and test of the moon, and other subsystems provide support, control, instruction and management services for the normal work of the payload.

According to the four scientific objectives of China's lunar exploration satellite project, Chang 'e-1 carried eight kinds of 24 scientific detection instruments weighing 130 kg, namely microwave detector system, gamma spectrometer, X-ray spectrometer, laser altimeter, solar high-energy particle detector, solar wind ion detector, CCD stereo camera and interference imaging spectrometer.

According to aerospace experts, the test of electric satellites is mainly used for the comprehensive test of some equipment with electronic performance, and the test of structural satellites is mainly to assess the rationality of structural design and the rationality of temperature control design of the whole satellite. At present, the structural manufacturing of these two prototypes has been completed, and the whole satellite test will be started before the end of the year. On this basis, the prototype satellite of Chang 'e-1 will be developed. According to reports, the whole initial sample testing stage will last until June 2007, and then it will enter the satellite sample star development stage.

In order to ensure the completion of the lunar exploration project, researchers designed 4 1 item reliability for the Changsanjia rocket undertaking the satellite launch mission to improve its carrying reliability.

Technical difficulties

1, Orbit Design and Flight Program Control

2. Three-vector control problem of satellite attitude control.

3. Adaptive design of satellite environment

4. Long-distance TT&C and communication "Chang 'e-1" satellite was developed by China Academy of Space Technology. It is mainly used to obtain three-dimensional images of the lunar surface, analyze the distribution characteristics of related material elements on the lunar surface, detect the thickness of lunar soil, and detect the space environment of the earth and the moon. Chang 'e-1 lunar exploration satellite consists of a satellite platform and a payload. The satellite platform was developed with the technology of Dongfanghong-3 satellite platform, and the researchers made adaptive modifications to eight subsystems, including structure, propulsion, power supply, measurement and control, and data transmission. Payload includes CCD stereo camera, imaging spectrometer, solar cosmic rays monitor, low-energy particle detector and other scientific detection instruments.

Chang 'e-1 lunar exploration satellite will be launched by Long March 3A carrier rocket in xichang satellite launch center in June 2007. After the satellite is launched, it takes 8 to 9 days to complete the phase modulation orbit, the earth-moon transfer orbit and the orbit around the moon, and carry out scientific exploration tasks. It will complete four scientific tasks, the primary purpose of which is to "portrait" the moon, that is, to obtain images and three-dimensional images of the moon surface through various means. In addition, it is necessary to analyze the distribution characteristics of useful elements and material types on the surface of the moon, and detect the thickness of lunar soil and the space environment of the earth and the moon.

According to experts, Chang 'e-1 satellite is two meters square. When the solar wing is deployed, it can reach18m at the longest, and its takeoff weight is 2350kg. It takes 10- 12 days for a satellite to fly near the moon. The design life of Chang 'e-1 is one year, and it will not return to Earth after completing its mission.

Carry a song

"Chang 'e I" will carry 3 1 song. After the successful launch, you can receive the songs returned by the satellite through TV and radio, but no download service is provided.

List of 3 1 songs played:

1 "Who doesn't say my hometown is good"

2 "Love China"

3 "Singing the Motherland"

4 Liang Zhu.

5 "My Country"

6 "Entering a New Era"

7 "Two Springs Reflecting the Moon"

8 Ode to the Yellow River

Qinghai-Tibet Plateau

10 Song of the Yangtze River

1 1 in the field of hope

12 the story of spring

13 Song of Seven Sons

14 My China Heart

15 "high mountains and flowing water"

The rising sun in Ran Ran on the grassland.

17 "alishan girl"

18 excerpt from Drunk Maids.

19 "unforgettable tonight"

20 "Singing and Laughing"

2 1 Spring Festival Overture

22 "Half Moon Climbs Up"

23 Excerpts from Dreams in the Garden

24 "Abundant and Vast Alashan"

25 "Good night"

26 Selected Songs of Twelve Muqams

27 "Pearl of the Orient"

28 "In that faraway place"

29 "I'm from China"

30 "Wish others a long time"

3 1 "We are ready"

Specially selected tracks:

1, National Anthem of the People's Republic of China

2. Dongfanghong

Starting step

After launch, Chang 'e-1 satellite will be sent into geosynchronous elliptical orbit, with the shortest distance of 500 kilometers from the ground and the longest distance of 70,000 kilometers. The lunar exploration satellite will orbit this orbit for 26 hours, and then enter a larger elliptical orbit by accelerating. The shortest distance from the ground is 500 kilometers, and the longest distance is1.2000 kilometers. It takes 48 hours to orbit once. Since then, the exploration satellite has been accelerating and began to "rush" to the moon. After about 83 hours of flight, when we are about to reach the moon, we will rely on the reverse booster of the control rocket to slow down. After being "captured" by the gravity of the moon, it became a satellite orbiting the moon, and finally flew around the moon in a polar orbit 200 kilometers away from the surface of the moon to take three-dimensional images.

It is estimated that the total time for the satellite to fly to the moon is 157 hours, which is close to 384,400 kilometers from the earth. In the past, the satellites launched by China were generally about 35,800 kilometers above the ground, which was almost 10 times.

Chang 'e project lunar exploration plan

Ouyang Ziyuan, chief scientist of China's lunar exploration project and academician of Chinese Academy of Sciences, said that Chang 'e-1 is the farthest satellite launched by China, with an average distance of 380,000 kilometers from the Earth. Prior to this, the farthest satellite launched by China was 40,000 kilometers above the ground.

The lunar exploration project will accomplish the following four scientific objectives:

1. Obtain the three-dimensional image of the lunar surface, finely divide the basic structure and geomorphic units of the lunar surface, and study the shape, size, distribution and density of impact craters on the lunar surface, providing basic data for the age division and early evolution history research of terrestrial planets, and providing basic data for the site selection of the lunar soft landing area and the site selection optimization of the lunar base.

2. Analyze the distribution characteristics of useful elements and material types on the lunar surface, mainly investigate the content and distribution of titanium, iron and other 14 elements with development and utilization value on the lunar surface, draw the full-moon distribution map of each element, the thematic map of lunar rocks, minerals and geology, find the rich areas of each element on the lunar surface, and evaluate the development and utilization prospect of lunar mineral resources.

3. Detecting lunar soil thickness, that is, using microwave radiation technology to obtain lunar soil thickness data, so as to obtain the age and distribution of the lunar surface, and on this basis, estimate the content, resource distribution and resource amount of helium -3 as fuel for nuclear fusion power generation.

Fourth, explore the space environment from the earth to the moon. The average distance between the moon and the earth is 380 thousand kilometers, which is located in the far magnetic tail region of the earth's magnetic field space. In this area, satellites can detect high-energy particles of solar cosmic rays and solar wind plasma, and study the interaction between solar wind and the moon, as well as the earth's magnetic field and the moon's magnetic tail.

Luan Enjie, deputy director of the Commission of Science, Technology and Industry for National Defense, director of the National Space Administration and commander-in-chief of the lunar exploration project,

The lunar exploration engineering system consists of five systems: lunar exploration satellite, launch vehicle, launch site, measurement and control and ground application, and will achieve the following five engineering objectives:

1) to develop and launch China's first lunar exploration satellite;

2) Master the basic technology of lunar exploration;

3) The first scientific exploration of the moon;

4) Preliminary construction of lunar exploration aerospace engineering system;

5) Accumulate experience for the follow-up lunar exploration project.

The lunar exploration project is the first stage of lunar exploration in China, that is, the development and launch of the first lunar exploration satellite. The star will orbit the moon and send the detected data back to the ground. The project consists of five systems: lunar exploration satellite, launch vehicle, launch site, measurement and control and ground application. It has been determined that the lunar exploration satellite mainly uses the platform of Dongfanghong III, the launch vehicle uses the Long March 3A rocket, the launch site uses the xichang satellite launch center, the detection system uses the existing TT&C network, and the ground application system is developed by Chinese Academy of Sciences.

The specific scheme is that the "Long March 3A" rocket takes off from Xichang Launch Center, and sends the "Chang 'e-1" satellite into geosynchronous transfer orbit to realize the separation of the star and the arrow. Finally, the satellite enters a circular orbit around the north and south poles of the moon to detect the moon. The height of the orbit from the surface of the moon is 200 kilometers.

With a design life of 1 year, Chang 'e-1 satellite will carry a variety of scientific instruments to explore the moon, such as stereo camera, imaging spectrometer, laser altimeter, microwave radiometer, solar cosmic rays detector and low-energy ion detector. During its mission around the moon, it mainly obtains three-dimensional images of the lunar surface, analyzes the distribution characteristics of useful elements and material types on the lunar surface, detects the thickness of lunar soil, and detects the space environment of the earth and the moon. Among them, the first three projects have not been carried out abroad, and the fourth project is the first time that China has obtained space environment parameters beyond 80 thousand kilometers. In addition, the United States has explored five kinds of resources on the moon, and China will explore 14 kinds, among which the important target is the helium -3 resources on the moon. Helium -3 is an important fuel that is safe, efficient, clean and pollution-free. According to statistics, helium -3 on the moon can meet the power supply needs of human beings 1 10,000 years. The content of helium -3 in lunar soil can reach 5 million tons.

observe

The launch of China's first lunar exploration satellite, Chang 'e-1, is just around the corner, and people's enthusiasm for seeing the Goddess Chang'e flying to the moon is increasing. The reporter learned from Jinying Travel Agency in Xichang, Sichuan Province, which organized the launching activities of the visit, that more than 1000 people have signed up for the visit. At the same time, the ticket price of the previously booked 800 yuan tour may be raised.

Why did Chang 'e-1 change its orbit for the first time at apogee?

On 25th 17: 55, Beijing Aerospace Control Center successfully implemented the first orbit transfer control for Chang 'e-1 satellite. This orbit change was carried out when the satellite was running to apogee, and the next three orbit changes were all carried out at perigee. Why did you choose apogee for the first orbit change?

Jaco, from Beijing Institute of Tracking Communication Technology, is the chief designer of TT&C system of lunar exploration project, and participated in the overall design of TT&C communication scheme of Chang 'e-1 satellite. He said that when satellites are in orbit change control, they are usually carried out at perigee and apogee, which can save the fuel carried on satellites to the greatest extent. The first orbit change of Chang 'e-1 satellite was carried out at apogee, in order to improve the orbit height of perigee.

"Only by changing the orbit at apogee can we improve the orbit height at perigee," Jaco said. "Similarly, to change the altitude at apogee, we must implement orbit change at perigee. After we raise the perigee altitude of the satellite for the first orbit change, it will increase the tracking time of the survey ship arranged near perigee, which is conducive to monitoring the orbit change process. Because the higher the satellite is from the ground, the longer the tracking control time of the monitoring station and the ship will be, which will lay a solid foundation for the three perigee orbits to be carried out in the future. "

Jaco said that according to the measurement and control plan, Chang 'e-1 satellite will undergo its first perigee orbit change on June 26, 65438. After the orbit change, the satellite will enter the orbit with an apogee of 7 1400 km, with a period of 24 hours. After the second perigee orbit change, the satellite will enter an orbit around the earth with an apogee of 12 1700 km and a period of 48 hours. In the third perigee orbit change, the satellite will enter the earth-moon transfer orbit and embark on a five-day trip to the moon.

According to the first law of Kepler's three laws of planetary motion: all planets have elliptical orbits, and the sun is located at a focal point of the ellipse. In polar coordinates with the sun S as the pole and the perihelion direction SP as the polar axis, the trajectory of the planet relative to the sun is an ellipse PP 1p2p' 1p', and PSP' = 2a represents the long diameter of the ellipse. This law also applies to satellite systems. Since it is an elliptical orbit, of course, there are places closest and farthest from the earth. So the farthest flying object in elliptical orbit (from the earth) is apogee, and the nearest is perigee.

Chang 'e I needs to leave the orbit around the earth three times.

After the launch, the Chang 'e-1 satellite will go around the earth five times in five days. The first stage is three turns, each turn 16 hours, the second stage is one turn in 24 hours, and the third stage is one turn in 48 hours.

A day or so after the rocket put the satellite into orbit, the command was injected into the ground to ignite the main engine of the satellite to change orbit, and the near field was raised to about 600 kilometers, so that the speed of the satellite was relatively reduced when it passed above the measurement and control station, which was convenient for subsequent control. The second, third and fourth ignitions are used to change the orbit and make the satellite accelerate continuously: the purpose of these three orbital changes is to accelerate. Every time the orbit is changed, the speed of the satellite will increase a little. After three times of accumulation, the satellite will accelerate to the minimum speed above10.965,438+06 km/s to enter the earth-moon transfer orbit and fly to the moon.

The importance of "track change"

On 24th 18: 29, after the satellite was successfully separated from the arrow, Chang 'e-1 satellite entered the super-geosynchronous orbit with perigee of 205km and apogee of 50930km and period of 16h. After the satellite "runs" in this orbit for one and a half times, it is expected to make the first orbit change on the afternoon of the 25th. After the orbit change, the perigee of the satellite orbit will be increased to about 600 kilometers from the earth. After the satellite is separated from the launch vehicle, it needs four orbital changes to gradually accelerate to the entrance speed of the earth-moon transfer orbit. It takes only a few minutes for each perigee acceleration, and it is necessary to send instructions to the satellite in a short time. The satellite engine must respond accurately, otherwise the satellite may fly in other directions.